Gearshift mechanism

ABSTRACT

A gearshift mechanism for a motorcycle ( 10 ) or other sequentially geared vehicle having a solenoid assembly ( 12, 14 ), a solenoid plunger ( 18 ), a switch apparatus ( 30, 32 ) and a linkage (22, 26). The switch apparatus ( 30, 32 ) has first and second switching positions and is operably connected to the solenoid assembly (12, 14). The linkage ( 22, 26 ) is secured to the solenoid plunger ( 18 ) and is connectable to a gearshift lever (28) of a motorcycle engine. The solenoid assembly ( 12 ) operates on actuation of the switch apparatus to its first switching position ( 30 ) causing movement of the solenoid plunger ( 18 ) in a first direction along the axis of the solenoid assembly ( 12, 14 ). The solenoid assembly ( 14 ) operates on actuation of the switch apparatus to its second switching position ( 32 ) causing movement of the solenoid plunger ( 18 ) in the opposite direction along the axis of the solenoid assembly ( 12, 14 ).

The invention relates to a gearshift mechanism for a sequentially gearedvehicle such as a motorcycle and, in particular, to a hand operablegearshift mechanism. Although the invention will be described herein inrelation to a gearshift mechanism for a motorcycle, it is to beunderstood that the invention is also applicable to other sequentiallygeared vehicles such as kit cars and karts.

A pivotally mounted gearshift lever is associated with a motorcycleengine for shifting the motorcycle up and down through its gears.Pivoting the gearshift lever a predetermined distance in a clockwise oranticlockwise direction away from a rest position effects a gearshift.The direction of pivotal movement of the gearshift lever is of coursedependent on whether the motorcycle is being shifted up or down a gear.On completion of the gearshift, by moving the gearshift lever thepredetermined distance in the required direction, the gearshift lever isreturnable to its rest position.

Conventionally the gearshift lever is linked to a foot-operatedgearshift pedal. This enables a motorcyclist to effect movement of thegearshift lever, and thereby effect gearshifts, using his foot to pushthe pedal up or down depending on whether he wishes to shift themotorcycle up or down a gear.

Before operating the gearshift pedal, a motorcyclist must close thethrottle and disengage the clutch. On completion of the gearshift, themotorcyclist re-opens the throttle and re-engages the clutch.

Operation of the gearshift lever by means of a conventional gearshiftpedal of course means that a motorcyclist must be able to move his footin order to operate the pedal. This may not be possible if themotorcyclist is disabled.

Similarly, a motorcyclist may encounter difficulties using theconventional gearshift pedal during negotiation of a tight bend. This isbecause a motorcyclist will lean into a tight bend to lower his centreof gravity and permit him to travel around the bend at a greater speedthan may otherwise be possible in an upright position. In doing somovement of the motorcyclist's foot closest to the road surface may belimited. If the foot closest to the road surface happens to be the footthat is required to operate the gearshift pedal, it may not be possiblefor the motorcyclist to move his foot to operate the pedal withoutbringing his foot into contact with the road surface.

U.S. Pat. No. 6,131,682 is directed to an electric solenoid shifter forshifting a motorcycle upwardly through its gears by pushing a buttonmounted on the handlebars of the motorcycle.

The shifter employs a cable that is secured, at one end, to thegearshift pedal and, at its other end, to a solenoid plunger locatedwithin a solenoid. During operation, the solenoid moves the solenoidplunger so that it pulls on the cable and, in turn, the gearshift pedal,causing the motorcycle to shift up a gear. In addition, the shifterincludes an ignition interrupter that interrupts ignition to the engineallowing a clutchless gearshift to be made during acceleration.

However, while the shifter disclosed in U.S. Pat. No. 6,131,682 permitsclutchless shifting of the motorcycle up through its gears, the flexiblecable does not permit shifting of the motorcycle down through its gears.The motorcyclist must operate the gearshift pedal with his foot toeffect a downward gearshift.

The shifter of U.S. Pat No. 6,131,682 would not therefore be suitablefor a motorcyclist who is unable to operate the gearshift pedal.

According to a first aspect of the invention there is provided agearshift mechanism for a sequentially geared vehicle comprising:

-   -   a solenoid assembly;    -   a solenoid plunger;    -   a switch apparatus, having first and second switching positions,        operably connected to said solenoid assembly; and a linkage,        secured to said solenoid plunger, that is connectable to a        gearshift lever of the engine of a said vehicle,        wherein:    -   said solenoid assembly operates on actuation of said switch        apparatus to its first switching position causing movement of        said solenoid plunger in a first direction along the axis of        said solenoid assembly; and    -   said solenoid assembly operates on actuation of said switch        apparatus to its second switching position causing movement of        said solenoid plunger in the opposite direction along the axis        of said solenoid assembly, characterised in that the gearshift        mechanism further comprises a cut-out timer operably connected        to said switch apparatus so that said cut-out timer temporarily        prevents combustion in said vehicle engine on actuation of said        switch apparatus to its first switching position, and a delay        timer operably connected between said first switching position        and said cut-out timer which delay timer causes activation of        the cut-out timer to be delayed for a predetermined length of        time after actuation of the switch apparatus. The cut-out timer        may comprise an ignition cut-out timer which temporarily        interrupts ignition to the vehicle engine.

Alternatively the cut-out timer comprises a fuel cut-out timer whichtemporarily interrupts flow of fuel to the vehicle engine. This isparticularly advantageous in fuel injection vehicles.

Although the gearshift mechanism according to the first aspect of theinvention is for any sequentially geared vehicle, it is particularly foruse with a motorcycle.

When the gearshift mechanism of the invention is fitted to a motorcycle,movement of the solenoid plunger in response to operation of thesolenoid assembly enables the gearshift mechanism to effectively replacehuman operation of the gearshift pedal.

Solenoid controlled movement of the gearshift lever is inherentlyquicker than manually controlled operation by means of a conventionalgearshift pedal. The gearshift mechanism of the invention can thereforereduce the overall length of time required to effect a gearshift.

The quickness of operation of the gearshift mechanism of the inventionlends itself to a racing application

According to a second aspect of the invention there is provided amotorcycle having a gearshift mechanism comprising:

-   -   a solenoid assembly;    -   a solenoid plunger;    -   a switch apparatus, having first and second switching positions,        operably connected to said solenoid assembly; and    -   a linkage, secured to said solenoid plunger, that is connectable        to a gearshift lever of the engine of said motorcycle,        wherein:    -   said solenoid assembly operates on actuation of said switch        apparatus to its first switching position causing movement of        said solenoid plunger in a first direction along the axis of        said solenoid assembly; and    -   said solenoid assembly operates on actuation of said switch        apparatus to its second switching position causing movement of        said solenoid plunger in the opposite direction along the axis        of said solenoid assembly,    -   characterised in that the gearshift mechanism further comprises        a cut-out timer operably connected to said switch apparatus so        that said cut-out timer temporarily prevents combustion in said        vehicle engine on actuation of said switch apparatus to its        first switching position, and a delay timer operably connected        between said first switching position and said cut-out timer.

Fitting of the gearshift mechanism of the invention to a motorcycle doesnot interfere with the conventional gearshift pedal. Movement of thegearshift lever in response to operation of the solenoid assembly willtherefore cause movement of the gearshift pedal as a result of thelinkage connected between the gearshift lever and the gearshift pedal.Similarly, movement of the gearshift lever in response to operation ofthe gearshift pedal will cause movement of the solenoid plunger alongthe axis of the solenoid assembly as a result of the linkage connectedbetween the gearshift lever and the solenoid plunger.

This enables a motorcyclist to use either the conventional gearshiftpedal or the gearshift mechanism of the invention to shift themotorcycle up or down a gear.

As a result, a motorcycle fitted with the gearshift mechanism of theinvention may be used by a motorcyclist who is unable to operate thegearshift pedal, or by a motorcyclist who is able to use the gearshiftpedal and does not wish to use the gearshift mechanism, withoutalteration of the motorcycle.

In another embodiment, the conventional gearshift pedal is not connectedto the gearshift lever. In yet other embodiments the gearshift pedal isnot present at all.

The provision of a switch apparatus to operate the solenoid assemblypermits remote operation of the solenoid assembly. This means that,while the solenoid assembly is preferably mounted on the motorcycleengine or chassis to reduce the length of the linkage between thesolenoid plunger and the gearshift lever, the switch apparatus may bemounted elsewhere on the motorcycle for easy access. For example, theswitch apparatus may be mounted on the handlebars, thereby rendering thesolenoid assembly hand-operable.

The gearshift mechanism may be fitted to a motorcycle so that actuationof the switch apparatus to the first switching position operates thegearshift lever to shift the motorcycle up a gear, and actuation of theswitch apparatus to its second switching position operates the gearshiftlever to shift the motorcycle down a gear.

The cut-out timer is operably connected to the switch apparatus so thatthe cut-out timer temporarily interrupts power to the motorcycle engineon actuation of the switch apparatus to its first switching position.

The cut-out timer permits clutchless shifting of a motorcycle up throughits gears. This is because cutting the power to the motorcycle engineremoves the load to the engine, thereby making it unnecessary to operatethe throttle or clutch when effecting a gearshift. The provision of thethe cut-out timer therefore reduces the length of time over whichacceleration is lost during a gearshift because the motorcyclist maykeep the throttle open during the gearshift. This has particularbenefits when the gearshift mechanism of the invention is used on aracing motorcycle where upward gearshifts must be as quick as possibleto achieve maximum acceleration.

The length of time for which the cut-out timer cuts the power to theengine is preferably set to the minimum amount of time to effect thegearshift so as to reduce the length of time over which acceleration islost. Typically, the cut-out timer is set to cut the ignition for 5 to60 ms so that acceleration is only lost for this amount of time. This iscompared to 1 to 1.5 s the length of time over which acceleration islost when the throttle is closed and the clutch is disengaged during aconventional gearshift.

In some embodiments, the cut-out timer may be set to cut power for alonger period of time such as 5 to 500 ms so that acceleration is lostfor this amount of time. Such periods however remain less than the timeover which acceleration is typically lost during a conventionalgearshift.

In order to further enhance the gearshift operation when using thegearshift mechanism of the invention, and to ensure that power to theengine is only cut for the minimum period of time, a delay timer isoperably connected between the first switching position of the switchapparatus and the cut-out timer.

A gearshift is not effected until the gearshift lever is moved apredetermined distance away from its rest position. This means that theinitial movement of the gearshift lever does not effect a gearshift.

The delay timer is therefore preferably adjusted so that the cut-outtimer only operates to cut power just before the gearshift lever reachesthe predetermined distance away from its rest position. This furtherreduces the period of time during which acceleration is lost.

The length of time for which the power is cut is of course determined bythe cut-out timer itself, and is preferably adjusted so thatacceleration is returned as soon as the gearshift is complete. This maybe before the solenoid plunger has returned the gearshift lever to itsrest position.

The switch apparatus may include a single switch having first and secondswitching positions such as, for example, a toggle switch. However,preferably, the switch apparatus may include first and second switches,the first switch defining the first switching position, and the secondswitch defining the second switching position.

The provision of two separate switches enables the motorcyclist toclearly determine whether he is about to shift the motorcycle up or downa gear, and thereby reduces the risk of a motorcyclist accidentallyshifting the motorcycle down a gear rather than up a gear, or viceversa.

The solenoid assembly may include a single solenoid that may beconnected to the switching apparatus so that current may flow through itin either direction depending on whether the switching apparatus isswitched to its first or second switching position.

In other embodiments, the solenoid assembly may include first and secondaxially aligned solenoids. In such embodiments the first solenoidoperates on actuation of the switching apparatus to its first switchingposition causing movement of the solenoid plunger in the first directionalong the axis of the solenoids. The second solenoid operates onactuation of the switching apparatus to its second switching positioncausing movement of the solenoid plunger in the opposite direction alongthe axis of the solenoids.

While the first and second solenoids in such embodiments may be twoseparate solenoids, they may, in other embodiments, be linked to form aone-piece twin solenoid.

The cut-out timer does not interrupt the power to the motorcycle engineon actuation of the switch apparatus to its second switching position.This is because shifting a motorcycle down a gear is primarily todecrease the speed of the motorcycle. It is not therefore desirable tobe able to maintain the throttle open during a downward gearshift. Amotorcyclist may therefore use the clutch when shifting a motorcycledown through its gears using the gearshift mechanism of the invention.Alternatively, if the motorcyclist is sufficiently skilled to use thethrottle to match the load that will be applied to the engine after thegearshift, the motorcyclist may shift the motorcycle down through itsgears without operating the clutch.

It is also possible to effect multiple downward gearshifts when theclutch is disengaged and the throttle is closed.

A first timer is preferably operably connected between the firstswitching position of the switch apparatus and the solenoid assembly anda second timer is preferably operably connected between the secondswitching position of the switch apparatus and the solenoid assembly.The timers control the duration of solenoid operation on actuation ofthe switch apparatus to either of its switching positions. The provisionof such timers means that the duration of solenoid operation is notlinked to the duration of actuation of the switch apparatus. The timerstherefore reduce the risk of a motorcyclist damaging the solenoidassembly by actuating the switch apparatus for too long. They alsoreduce the risk of the motorcyclist not actuating the switch apparatuslong enough to effect a gearshift.

The timers may be omitted from mechanisms intended for use on racingmotorcycles. This is because the skill of a racing motorcyclist is suchthat he can determine the length of time required to operate thesolenoid assembly and can therefore actuate the switch apparatusaccordingly. Racing motorcyclists would not otherwise be able to obtainneutral unless a gearshift pedal was fitted. This is because neutral islocated between first and second gears. Therefore, to obtain neutralfrom first gear, a motorcyclist must cause pivotal movement of thegearshift lever, in the upward gearshift direction, a distance that isnot as great as the distance required to effect the upward gearshiftfrom first gear to second gear. It is envisaged that usually a roadversion of a motorcycle incorporating the invention will include timersto effect timed operation of the solenoid, although this will not alwaysbe the case.

Advantageously the timers are adjustable.

The linkage connecting the gearshift plunger to the gearshift lever onthe motorcycle engine preferably includes a connector rod having athreaded end and a spherical bush mounted on the threaded end.

The provision of the threaded end on the connector rod permitsadjustment of the overall length of the linkage to ensure that anyfreeplay between the linkage and the gearshift lever is minimised.

The gearshift lever is a pivotally mounted member and so travels in anarc during a gearshift operation. This means that on motorcycles wherethe arc is pronounced, the gearshift lever may cause the connector rodto travel at a gradually increasing angle to the solenoid assembly axisrather than along the solenoid assembly axis. This may in turn pull thesolenoid plunger into contact with the housing surrounding the solenoidassembly, or the solenoid assembly itself.

To ensure that such contact does not occur, and thereby reduce any wearor losses that may be caused by such contact, the connector rod mayinclude a universal joint that permits articulation of the connectorrod. Such articulation of the connector rod allows a certain degree offreeplay to ensure that the solenoid plunger only travels along thesolenoid assembly axis. The solenoid assembly may be pivotablymountable. Other arrangements would be possible, including a loosefitting solenoid plunger and connector rod.

A preferred embodiment of the invention will now be described, by way ofa non-limiting example, with reference to the accompanying drawings inwhich:

FIG. 1 shows a motorcycle incorporating a gearshift mechanism accordingto an embodiment of the invention;

FIG. 2 shows first and second solenoids of the gearshift mechanism ofFIG. 1;

FIG. 3 shows a schematic illustration of an embodiment of the gearshiftmechanism of FIG. 1;

FIG. 4 is a schematic representation of a second embodiment of thegearshift of FIG. 1; and

FIG. 5 is a schematic representation of a third embodiment of thegearshift of FIG. 1.

A motorcycle 10 incorporating a gearshift mechanism according to anembodiment of the invention is shown in FIG. 1.

The gearshift mechanism includes first and second axially alignedsolenoids 12,14 (FIG. 2) housed within a cylindrical housing 16 mountedon the chassis of the motorcycle 10.

A solenoid plunger 18 is located within the solenoids 12,14 and isconnected, at one end thereof, to the first end 20 of a connecting rod22. The solenoid plunger 18 is made from a magnetic material.

The connecting rod 22 is threaded at its other end 24 and includes aspherical bush 26 mounted thereon. The spherical bush 26 is secured tothe first end 27 of an elongate gearshift lever 28. The other end 29 ofthe gearshift lever is pivotally mounted on the motorcycle engine.

The length of the linkage extending between the solenoid plunger 18 andthe gearshift lever 28, defined by the connector rod 22 and sphericalbush 26, is adjusted to minimise freeplay between the linkage and thecomponents 18,28 between which it is connected. Such adjustment isperformed by adjusting the position of the spherical bush 26 on thethreaded end 24 of the connector rod 22. The connector rod 22 is made ofa non-magnetic material.

First and second switches 30,32 are mounted on the handlebars 33 of themotorcycle 10. Each of the switches 30,32 is operably connected to arespective one of the solenoids 12,14, via a control box 34 that housesfirst and second timers 42,44, via a wiring loom.

The first switch 30 is, in addition, operably connected to a cut-outtimer comprising an ignition cut-out timer 36 (FIG. 3) connected to anignition feed 38. It is to be understood that the cut-out timer couldalso comprise a fuel cut-out timer connected to a fuel injection feed,for example.

In the embodiment shown in FIG. 1, the control box 34, via which thefirst and second switches 30,32 are connected to the solenoids 12,14, islocated behind the seat 40 of the motorcycle 10. The control box 34includes first and second timers 42,44 (FIG. 3). The first timer 42 isconnected between the first switch 30 and the first solenoid 12. Thesecond timer 44 is connected between the second switch 32 and the secondsolenoid 14.

Each of the timers 42,44 comprises a monostable circuit with a variableresistor such as a trim pot adjuster.

A series circuit containing the first switch 30, the first timer 42 andthe first solenoid 12 is formed with the motorcycle battery 48 connectedto control box 34 via ignition feed 38, between the first switch 30 andthe first solenoid 12.

Similarly, a series circuit containing the second switch 32, the secondtimer 44 and the second solenoid 14 is formed with the motorcyclebattery 48 connected between the second switch 32 and the secondsolenoid 14.

The two solenoids 12,14 face in opposite directions and thereforepolarity in the first solenoid 12, is opposite to that in the secondsolenoid 14.

First and second power control modules (PWR) 50,52 control the powersupplied to the solenoids 12,14. First and second interface modules58,60 perform the electrical level shifting and provide the isolationthat is required between the internal electronics and the outsidecabling. The components are linear electronic controlling power MOSFETS.

An ignition PWR control module 54 is connected in series between theignition feed 38 and the ignition cut-out timer 36. This component maybe a single or multiple unit depending on the type of ignition used bydifferent engines.

An internal power supply unit (PSU) 56 provides the necessary powersupply for the internal electronics. All control box 34 components areeither linear or logic electronics.

In order to shift the motorcycle 10 up a gear, the motorcyclist actuatesthe first switch 30.

On actuation of the first switch 30, the series circuit containing thefirst solenoid 12 is completed, causing a current to pass through thefirst solenoid 12. Consequently the first solenoid 12 generates anelectro-magnetic field. The direction of the current passing through thefirst solenoid 12 is such that the polarity of the solenoid causes thesolenoid plunger to move into the first solenoid 12 away from thegearshift lever 28.

Movement of the solenoid plunger 18 is transmitted via the linkagedefined by the connector rod 24 and the spherical bush 26 to thegearshift lever 28, and thereby causes the gearshift lever 28 to pivotanticlockwise around the pivotally mounted end 29 thereof. Such movementof the gearshift lever 28 shifts the motorcycle 10 up a gear. In otherembodiments of the invention an anticlockwise movement of the gearshiftlever 28 could effect a downward gearshift.

Completion of the circuit on actuation of the first switch 30 initiatesthe first timer 42. The first timer 42 breaks the circuit on expirationof a predetermined period. The duration of the period is determined bythe time required for the solenoid 12 to move the solenoid plunger 18the required distance to effect the upward gearshift. An adjuster Aconnected to the first timer 42 may be used to alter the duration of theperiod.

When the first timer 42 breaks the circuit, the first solenoid 12 ceasesto generate the electromagnetic field and allows the plunger 18 to moveback out of the solenoid 12. This movement of the solenoid plunger 18brings the gearshift lever 28 back to its rest position.

On actuation of the first switch 30, the pre-delay timer 46 alsoinitiates the cut-out timer 36. On expiration of a predetermined period,the pre-delay timer 46 initiates the ignition cut-out timer 36 tooperate the ignition PWR control module 54 which effects an ignitioninterrupt sequence and cuts ignition to the motorcycle engine for apredetermined time.

The delay set by the pre-delay timer 46, and the period of time duringwhich the ignition cut-out timer 36 operates the ignition PWR controlmodule 54 to cut ignition to the motorcycle engine, is set so that theperiod during which acceleration is lost is minimised. Adjuster C of theignition cut-out timer 36 may be used to adjust the delay provided bythe pre-delay timer 46.

While ignition to the engine is cut, the load to the motorcycle engineis removed. It is therefore possible to effect an upward gearshift withthe motorcycle throttle open. This means that when ignition to themotorcycle engine is resumed, after the upward gearshift, the throttleis already open. The period during which acceleration is lost istherefore further minimised.

In order to shift the motorcycle 10 down a gear, the motorcyclistactuates the second switch 32.

On actuation of the second switch 32, the series circuit containing thesecond solenoid 14 is completed, causing a current to pass through thesecond solenoid 14. Consequently the second solenoid 14 generates anelectromagnetic field. The direction of the current passing through thesolenoid 14 is such that the polarity of the solenoid causes thesolenoid plunger to move into the second solenoid 14 towards thegearshift lever 28.

Movement of the solenoid plunger 18 is transmitted via the linkagedefined by the connector rod 22 and the spherical bush 26 to thegearshift lever 28, and thereby causes the gearshift lever 28 to pivotclockwise around the pivotally mounted end 29 thereof Such movement ofthe gearshift lever 28 shifts the motorcycle 10 down a gear.

Completion of the circuit on actuation of the second switch 32 initiatesthe second timer 44. The second timer 44 breaks the circuit onexpiration of a predetermined period. The duration of the period isdetermined by the time required for the solenoid 14 to move the solenoidplunger 18 the required distance to effect the downward gearshift. Anadjuster B connected to the second timer 44 may be used to alter theduration of the period.

When the second timer 44 breaks the circuit, the second solenoid 14ceases to generate the electro-magnetic field and allows the plunger 18to move back out of the solenoid 14. This movement of the solenoidplunger 18 brings the gearshift lever 28 back to its rest position.

The ignition cut-out timer 36 does not cut the ignition to themotorcycle engine during a downward gearshift. The motorcyclist musttherefore disengage the clutch during the downward gearshift or operatethe throttle to match the load that will be applied to the engine afterthe gearshift.

FIGS. 4 and 5 illustrate further embodiments of the gearshift mechanismthat may be incorporated into a motor cycle of the type shown in FIG. 1.Components which are common to the embodiments shown in FIG. 3 and tothe embodiment shown in FIGS. 4 and 5 have been given the same referencenumerals for consistency.

Referring now to FIG. 4, a second embodiment of the gearshift mechanismwhich may be incorporated into the motor cycle of FIG. 1 is shown.

The mechanism comprises a third interface module 70 and a third switch72. The third switch 72 allows a rider to switch between a road settingand a race setting for example. When the rider selects the road setting,the ignition cut-out timer will be set to cut ignition for apredetermined length of time. When the rider selects the race setting,the ignition cut-out timer will be set to cut the timer for a shorterperiod of time. This is because when a motorcycle is moving at a highspeed, less time is required to change gear.

Referring to FIG. 5, a further embodiment of the gearshift mechanism isshown. In this embodiment, there is a fourth (tachometer) interfacemodule 74 associated with tachometer input 76 and a fifth interfacemodule 78 associated with fifth switch 80. The presence of thetachometer input which is fed into the system via the tachometerinterface 74 means that the ignition cut-out timer 36 may be set inaccordance with the revolutions per minute of the engine. This meansthat instead of the ignition cut-out timer cutting ignition to theengine for a predetermined length of time, the time that the ignitionwill be cut will be inversely proportional to the number of revolutionsper unit time of the engine. This means that when the motorcycle ismoving at a high speed, the ignition will be cut for a shorter period oftime. This embodiment of the invention may be used in conjunction with aroad/race selector of the type described herein above with reference toFIG. 4.

It is possible to incorporate different combinations of the featuresshown in the embodiments of FIGS. 4 and 5 into a gearshift mechanismaccording to the present invention.

In other embodiments of the invention, the first and second axiallyaligned solenoids 12,14 may be linked together to form a one-piece twinsolenoid.

In yet other embodiments, the connector rod 22 may include a universaljoint intermediate its two ends so that a first portion of the connectorrod 22 may be articulated relative to a second portion. Sucharticulation may be used to compensate for the arc shaped path followedby the end 27 of the gearshift lever 28 during an upward or downwardgearshift.

When the gearshift mechanism according to the invention is used on aracing motorcycle, the first and second timers 42,44 may be dispensedwith.

In such embodiments, the period of time over which the first and secondsolenoids are connected to the motorcycle battery 48 is determined bythe length of time the respective switches 30,32 are operated by themotorcyclist.

Connecting the solenoids 12, 14 to the battery 48 in this way enablesthe motorcyclist to obtain neutral. This is because neutral is locatedbetween the first and second gears of a motorcycle and is obtained, fromfirst gear, by moving the gearshift lever, in a clockwise direction, adistance that is less than the distance required to shift the motorcycleup to second gear. This is not possible when the first timer 42 is usedto control connection of the first solenoid 12 to the battery 48 and agearshift pedal is not provided. This is because the timer 42 is set toconnect the solenoid 12 to the battery 48 for a period of time that islong enough to effect the upward gearshift. The timer 42 will alwaystherefore effect an upward gearshift to second gear, and not neutral.

1. A gearshift mechanism for a sequentially geared vehicle comprising: asolenoid assembly; a solenoid plunger; a switch apparatus, having firstand second switching positions, operably connected to said solenoidassembly; and a linkage, secured to said solenoid plunger, that isconnectable to a gearshift lever of the engine of a said vehicle,wherein: said solenoid assembly operates on actuation of said switchapparatus to its first switching position causing movement of saidsolenoid plunger in a first direction along the axis of said solenoidassembly; and said solenoid assembly operates on actuation of saidswitch apparatus to its second switching position causing movement ofsaid solenoid plunger in the opposite direction along the axis of saidsolenoid assembly, characterised in that the gearshift mechanism furthercomprises a cut-out timer operably connected to said switch apparatus sothat said cut-out timer temporarily prevents combustion in said vehicleengine on actuation of said switch apparatus to its first switchingposition, and a delay timer operably connected between said firstswitching position and said power cut-out timer which delay timer causesactivation of the cut-out timer to be delayed for a predetermined lengthof time after actuation of the switch apparatus.
 2. A gearshiftmechanism as claimed in claim 1 wherein the sequentially geared vehicleis a motorcycle.
 3. A gearshift mechanism as claimed in claim 1 whereinsaid switch apparatus includes first and second switches, said firstswitch defining said first switching position and said second switchdefining said second switching position.
 4. A gearshift mechanismaccording to claim 1 further comprising means for adjusting the time forwhich the cut-out timer temporarily prevents combustion in the vehicleengine.
 5. A gearshift mechanism according to claim 1 further comprisinga tachometer, and means for connecting the power cutout timer to theoutput of the tachometer thereby varying the time for which the powercut-out timer temporarily interrupts power to the vehicle engineaccording to the number of revolutions per unit of time at which theengine is operating.
 6. A gear shift mechanism according to claim 1wherein the cut-out timer comprises an ignition cut-out timer.
 7. Anapparatus according to claim 1 wherein the cut-out timer is a fuelcut-out timer.
 8. A gearshift mechanism as claimed in claim 1 whereinsaid solenoid assembly includes first and second axially alignedsolenoids, said first solenoid operating on actuation of said switchapparatus to its first switching position causing movement of saidsolenoid plunger in said first direction along the axis of saidsolenoids, and said second solenoid operating on actuation of saidswitch apparatus to its second switching position causing movement ofsaid solenoid plunger in said opposite direction along the axis of saidsolenoids.
 9. A gearshift mechanism as claimed in claim 1 wherein saidsolenoid assembly includes a one-piece twin solenoid.
 10. A gearshiftmechanism as claimed in claim 1 wherein said cut-out timer interruptsignition to said vehicle engine for 5 to 500 ms.
 11. A gearshiftmechanism as claimed in claim 10 wherein said cut-out timer interruptsignition to said vehicle engine for 5 to 60 ms.
 12. A gearshiftmechanism as claimed in claim 1 or claim 10 further comprising a firsttimer operably connected between said first switching position and saidsolenoid apparatus, and a second timer operably connected between saidsecond switching position and said solenoid apparatus.
 13. A gearshiftmechanism as claimed claim 1 wherein said linkage includes a connectorrod having a threaded end and a spherical bush mounted on said threadedend.
 14. A gearshift mechanism as claimed in claim 13 wherein saidconnector rod includes a universal joint that permits articulation ofsaid connector rod.
 15. A motorcycle including a gearshift mechanism asclaimed in claim
 1. 16. A motorcycle having a gearshift mechanismcomprising: a solenoid assembly; a solenoid plunger; a switch apparatus,having first and second switching positions, operably connected to saidsolenoid assembly; and a linkage, secured to said solenoid plunger, thatis connectable to a gearshift lever of the engine of said motorcycle,wherein: said solenoid assembly operates on actuation of said switchapparatus to its first switching position causing movement of saidsolenoid plunger in a first direction along the axis of said solenoidassembly; and said solenoid assembly operates on actuation of saidswitch apparatus to its second switching position causing movement ofsaid solenoid plunger in the opposite direction along the axis of saidsolenoid assembly, characterised in that the gearshift mechanism furthercomprises a cutout timer operably connected to said switch apparatus sothat said cut-out timer temporarily prevents combustion in said vehicleengine on actuation of said switch apparatus to its first switchingposition, and a delay timer operably connected between said firstswitching position and said power cut-out timer.